This is a lyrical masterpiece of devotion of Vishnu by Sri Yamunacharya, the predecessor of Sri Ramanuja. Sanskrit text, with English transliteration, translation and notes.
There is only one sin -- and that sin is weakness. When I was a boy, I read Milton's Paradise Lost. The only good man I had any respect for was Satan. The only saint is the soul who never weakens, faces everything, and determines to die game.
-Swami Vivekananda